This section provides background information related to the present disclosure, which is not necessarily prior art.
Heating, ventilation, and air cooling (HVAC) assemblies and systems include, for example, a blower scroll, inlet and outlet ducts, irregular shaped chambers and cavities, and non-uniform cross-section ducts with registers and restrictive heat exchangers, such as heater cores and evaporators. As airflow passes through such HVAC systems and assemblies, various noises may occur, such as hollow tones between about 500 Hz. to about 1500 Hz. Because only a small space is available under the HVAC assembly for the instrument panel, conventional noise control approaches using, for example, mufflers and/or sound absorbers can be costly and can negatively affect airflow performance. Sound suppressing devices and methods that selectively target and suppress sounds caused by airflow flowing through an HVAC assembly without sacrificing airflow strength and heating/cooling performance would thus be desirable.